<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>小三角</title>
    <style>
        .box1{
            width: 0;
            height: 0;
            border-top: 10px solid pink;
            border-right: 10px solid red;
            border-left: 10px solid blue;
            border-bottom : 10px solid green;
        }
        .box2{
            width: 0;
            height: 0;
            border: 50px solid transparent;
            margin: 100px auto;
            border-left-color: pink;
            /* 照顾低版本浏览器 */
            line-height: 0;
            font-size: 0;
        }
        .jd{
            position: relative;
            width: 120px;
            height: 249px;
            background-color: pink;
        }
        .jd span{
            position: absolute;
            right: 15px;
            top: -20px;
            width: 0;
            height: 0;
            line-height: 0;
            font-size: 0;
             border: 10px solid transparent;
             border-bottom-color: pink;
        }
    </style>
</head>
<body>
    <div class="box1"></div>
    <div class="box2"></div>
    <div class="jd">
        <span></span>
    </div>
</body>
</html>